I didn't understand for quite some time why prosecutors couldn't go after and find tax perpetrators who they knew had offshore structures. Until I finally found out how simple it is. One of two or both reasons:

1)As laid out in this article by the BBC, there simply is no record of the true beneficial owner.

2)The jurisdictions have no legal agreements with western countries to hand over their records.

Example: Person A in western country X has an offshore structure going through countries Y and Z, both of which have no legal agreement with country X. Now through some leaks and witnesses, prosecutors in country X know that person A is hiding something in Y and Z, but they cannot prove it. They cannot obtain those records legally, if there even are any.

That's what must be tackled.